1. Field of the Invention
The present invention relates to underwater acoustic measurement systems and, more particularly, to acoustic Doppler current profilers used to measure wave directional spectra and surface wave height.
2. Description of the Related Technology
An acoustic Doppler current profiler (ADCP) is an instrument that obtains profiles of water velocity by transmitting sound of known frequency into the water and measuring the Doppler shift of reflections from scatterers, which are assumed to be passively moving with the water. One such ADCP is disclosed in assignee's U.S. Pat. No. Re. 35,535, which is incorporated by reference. For use in applications such as offshore platforms and port entrances, it is desirable for such instruments to profile the near-surface currents by looking from a platform or piling. One such ADCP is disclosed in assignee's U.S. Pat. No. 6,052,344, which is incorporated by reference. Applications for wave measurement ADCP include saltwater and freshwater bodies such as oceans, seas and lakes.